Arduino Forum

Forum 2005-2010 (read only) => General => Frequently-Asked Questions => Topic started by: mitcho on Mar 29, 2006, 05:44 am

Title: Rx/Tx pins
Post by: mitcho on Mar 29, 2006, 05:44 am
Hi guys,
i wish to connect this bluetooth modem to my board ( i have to connect it to the Rx/Tx pins. can anyone tell me which pins are these?

if i connect this modem to these pins and the power, will it work?

PS- if there are any arduino users in australia who wouldnt mind me calling them to ask a few questions let me know.
Title: Re: Rx/Tx pins
Post by: mellis on Mar 29, 2006, 01:13 pm
RX is digital pin 0, TX is digital pin 1.  They're labelled on the new boards; picture here:
Title: Re: Rx/Tx pins
Post by: mitcho on Mar 30, 2006, 03:42 am
Thanks guys. i need to know because i ordered this

I heard from someone on the sparkfun forums that in order to use the BlueSMiRF I need to bypass the RS232 interface on the board. Is this true?

If so - I don't know how to do this? How can i bypass the RS232 interface????

Thanks! would appreciate your advice.
Title: Re: Rx/Tx pins
Post by: leKuk on Mar 30, 2006, 02:23 pm

for rx and tx you don't need to bypass anything as far as i can tell. as Mellis said, digital pin 0 and 1 are marked rx and tx. all data you send through the serial interface does flow through your usb-port to your computer and at the same time through the tx-pin. incoming data is read both from the usb port (coming from your computer) or the rx-pin on arduino.

this should be true as long as you don't assign any other function (digital in or out) to those pins.

as for RTS and CTS (ready-to-send/clear-to send) on your bluetooth module you can just connect them to each other i guess. those lines are used for flow control, i.e. to signalize that a device is ready to send or receive data. if you experience problems you might bypass/grab those line from somewhere on the board. maybe someone more familiar with the board will help you then.

see  >>>"flow control" for more info.

AND someone correct me if i'm wrong please!

please post your results here! i'm thinking of going bluetooth too.

k u k
Title: Re: Rx/Tx pins
Post by: mitcho on Mar 31, 2006, 01:27 am
Well the components are on their way being shipped. so when they get here i can start playing immediatley and will post my progress - probably in a new thread or something..

Thanks for your info regarding this matter - you know quite a bit and it willl be helpful to know!

Regarding the RTS and CTS - if anyone knows wherher i have to bypass/grab those lines from somewhere on the board, please let me know!

Title: Re: Rx/Tx pins
Post by: fallen on Apr 01, 2006, 07:41 am
Hi! mitcho , I had already add a bluetooth modem to Arduino last month , and it works very well , you can see the pic :

I don't know your bluetooth modem works at 3.3v or 5v , my modem is work at 3.3v ,so I need to turn 5v to 3.3 .  the leaved things is just connect the pin0(Rx) of Arduino to the TX of your modem , pin1(Tx) of Arduino to the RX of your modem , than connect the BT to your PC or PDA , you can get the date from Arduino and can send date to it just like there is a series cable , and you can use  Arduino IDE  to download program to the board via BT modem .
Title: Re: Rx/Tx pins
Post by: mitcho on Apr 01, 2006, 08:45 am
that is excellent you got working!! - for me i could not use the same modem u used. u use a very BIG modem - i need something small that can be 'wearable' (like the one i ordered < i will use this one when it arrives!

but i am very happy that yours works. this means that it can be done successfully! CONGRATULATIONS!

can i have your email address, so i can contact you about setup details.

Thankyou for your information!!!
Title: Re: Rx/Tx pins
Post by: fallen on Apr 01, 2006, 11:53 am
Hi ! mitcho . I only know little English ( I'm a Chinese) , my email : fallen11
Title: Re: Rx/Tx pins
Post by: mitcho on Apr 01, 2006, 05:59 pm
Oh ok - i see now. the modem is the small chip. did you have to attach to big board to get the power to 3v, or is it because you use the big board for other thing.

i can use 5v to power modem i ordered so i will just attach it straight onot arduino.

i will email you soon. Thankyou for your advice!
Title: Re: Rx/Tx pins
Post by: fallen on Apr 02, 2006, 07:05 am
The big board used to control the motor of my robot , you are so luckly  ;),  you can use 5v to power modem , it make things very easy , if I live at USA , I will buy one modem like yous , but I in China , the postage is very costly  :(
Title: Re: Rx/Tx pins
Post by: mitcho on Apr 02, 2006, 09:02 am
i do not live in USA - i live in australia - postage was $30 Australian.

Oh well.

I did not know that it was able to be powered by 5V when i bought it, but i found out later its between 3 and 6V, so 5V will work good!

I will let you know when i get package!

Your project is VERY cool! do you have a site about it?
Title: Re: Rx/Tx pins
Post by: fallen on Apr 03, 2006, 09:07 am
Hi !
I only write some articles in my blog about it (but only in Chinses) :

It's a net control robot , you can control it , see it ,  receive the date from it  in the browser(with flash player)

but the server is just my PC , so I can't open it all the day.
and I make a video of it , you can see at :   but it is big (30M, 20min)

If you want to try , you can leave a time(the time here is  UTC+8)as a reply here(english) :
then at that time we arranged , if I open my server , you can try to  control my robot.